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  • Writer's pictureDr. H. Singh, ND

"Right on Time!" Guide to Improving Natural Pregnancy Rates

Trying to conceive can appear to be quite tedious when you consider the number of methods to track your cycle, predict ovulation and trying to determine which days of the calendar should be marked with "Fertile Window (FW)."

There definitely is no shortage of courses or information available online on how to 'time' intercourse, each method promising to increase your chances of success. But which of these methods has reliable clinical evidence support increased pregnancy rates? And what is the trade off with regards to stress around this whole process?

A recently published systematic review sought out the answers to the above questions to help inform healthcare providers and Patients alike on how to best start your journey for a successful pregnancy and they compared some of the common methods you may have already heard about. Something these methods have in common is that they aim to help determine the 'fertile window.'

The fertile window is a period of time, usually up to 5 days in length, prior to ovulation. These are the days these methods suggest having timed intercourse with the hope of increasing chances of fertilization and therefore pregnancy (assuming implantation successfully occurs).

Ovulation Predictor Kits (OPKs):

At home urine tests that can check for the concentration of luteinizing hormone (LH) and some other tests will check for levels of estrogen (estrone-3-glucuronide or E3G for short) in the urine to help detect ovulation.

This method was found to have moderate quality evidence suggesting that using OPKs to help determine your fertile window for timed intercourse can probably increase your chances of a positive urine pregnancy test, clinical pregnancy (ultrasound confirming cardiac activity) and a live birth (carrying to term and giving birth to a healthy child). The review found that OPKs were able to increase the live birth rate by about 36% relative to the chances of live birth rate by trying to conceive without OPK use.

As you will see further below, this method is one of the best available for supporting chances of successful outcomes and it is relatively easy to use compared to some of the methods mentioned below. The downside to this method can be cost of purchasing the test strips and any associated subscriptions for applications needed for the test strip.

It is important to make note that a subset of individuals with PCOS may experience reduced efficacy using this method if they have elevated LH levels at various times of the month and not just around ovulation. Many individuals with PCOS can still successfully use this method. In some cases I will encourage Patients trying this method for the first couple cycles to confirm their OPK positive test result with a blood test to help confirm ovulation and determine if the OPK may be a reliable method for them to use to predict their fertile window.

Fertility Awareness-Based Methods (FABM):

This includes cervical mucus monitoring, basal body temperature monitoring and/or calendar tracking apps. However, due to the available evidence on these methods being classified as 'very low quality evidence' and the number of studies being scarce there is insufficient clinical evidence according to the researchers to determine if these methods are actually reliable or able to increase chances of a successful pregnancy.

A word of caution for basal body temperature (BBT) monitoring: in my experience over the years of clinical practice I have noticed on many occasions that BBT significantly increased feelings of anxiety, stress and contributed to low mood for numerous Patients. I never recommend this method to my Patients due to this observation as well as the scarcity of research supporting its use compared to OPKs. I suspect that taking your basal body temperature first thing in the morning, every single day, can be a hurtful daily reminder of the struggle with infertility and the thoughts we start our day with can affect the mood for the day. In many cases, Patients reported to me a significant improvement in their mood and a significant reduction in stress levels within days of stopping BBT charting. Fertile window and cycle monitoring can be important components of supporting successful pregnancy, but is is crucial to evaluate which method can help you and be the least invasive in your daily routine. The method that works best for you may differ from another, and therefore it is best to speak with your fertility healthcare team to discuss pros and cons of each method for you specifically.

This article is being shared as educational content and is in no way a replacement for medical advice or medical care, it is advised that anyone concerned about their Health should speak with their Naturopathic Doctor. Please discuss with your healthcare provider and only make changes to your medications regimen if recommended by your doctor and under their guidance and supervision.


  1. Gibbons, T., Reavey, J., Georgiou, E. X., & Becker, C. M. (2023). Timed intercourse for couples trying to conceive. Cochrane Database of Systematic Reviews, 2023(9).

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